Hydraulic compress



Nov. '24, 1936. s HUBBERT HYDRAULIC poMP Ess' 7 sheets s heet 1 Filed July 17, 1935 5 1551/5 5. fll/BBERZ A TTOR/VEYS Nov. 24, 1936. s; H E T I 2,061,658

HYDRAULIC coMrREss Filed July '17, 1933 7 Sheets-Sheet 2 ATTORNEYS 1936? s. HUBBERT HYDRAULIC GOMPREYSS 7 Sheets-Shet 3 Filed July 17, 1953 v I 12.1 I

ATTORNEYS? NOV. 24, 1936. HUBBERT 2,061,658

HYDRAULIC cdMPREss Filed July 17, 1933 1 7 Sheets-Sheet 4 IIYVEWTOR LESLIE s. #0555.

nrr omviys Nov-r24, 1936. 1.. s. HUBBERT 2,061,658

- HYDRAULIC QOMPRESS I Filed Juiy 17, 1933 7 Sheet-Sheet 5 Nov. 24; 1936. 1... s; HUBBERT g HYDRAULIC COMPRESS Filed July 17. 1933 7 Sheets-Sheet 'uwsnlro/i" LESL/f s. HUBEERT.

Br I

Patented Nov. 24, 1936 UNITED STATES PATENT OFFICE mesne assignments, to The Hydraulic Press Corporation, Inc., Wilmington, Del., a corporation of Delaware Application July 1'1, 1933, Serial 110,680,711

'z (o1.1oo-19) This invention relates to compresses and especially to hydraulic compresses wherein the cotton or other compressed material is subjected to the application of hydraulic compressing force. I

An object of my invention is to provide a hydraulic compress wherein the cotton or other material to' be compressed is confined on its sides and ends by movable doors, and compressed by pressure applied from below and exerted against a stationary head above the cotton; and hydraulic pressure is applied to the ends.

Another object is to provide a hydraulic compress actuated by-hydraulic motors consisting of hydraulic cylinders, wherein the initial compressing force is provided by auxiliary hydraulic cylinders and the final compressing force by these aided by a main cylinder whose action is delayed and automatically introduced when the hydraulic pressure, built up against the resistance of the cotton, reaches a predetermined value;

Another object is to provide a hydraulic compress wherein the various hydraulic motors or cylinders are operated by a variable delivery reversible pump.

Another object is to provide a hydraulic compress wherein the press is provided with false doors or movable platforms cooperating with the doors of the press to aid in the safety and convenience of loading and unloading the cotton I in the press.

Another object is to provide ajhydraulic compress having hydraulically-operated end doors and side doors which mutually interlock in their closed positions:

Another object is to provide a surge valve for a hydraulic compress wherein the valve memoutput of the pump until this release has taken place.

Another object is to provide a hydraulic compress wherein the doors are actuated by an independent hydraulic pump which is automatically returned to its neutral discharge position when the doors of the compress reach their closed position.-

Another objectjs to provide a method of compressing yieldable materials wherein a low pressure is initially applied and a high pressure subsequently applied when the initial pressure rises to a predetermined value.

In the drawings: Figure 1 is a front elevation of the hydraulic compress of my invention, showing the associated hydraulic circuit and the various units thereof.

Figure 2 is a front elevation, partly in central vertical section, of the apparatus in Figure 1.

Figure 3 is a side elevation of the hydraulic compress shown in Figure 1.

Figure 4 is a central vertical section along the line 4-4 of Figure l, with the side doors and false doors in a lowered position.

Figure 5 is a horizontal cross section through the hydraulic compress of Figure 1 along the line 55 thereof.

Figure 6 is an enlarged central vertical section through the relief and by-pass valve shown in Figure 1.

Figure 7 is an enlarged horizontal cross sec tion through the door-actuating pump for the hydraulic compress, along the line 1-1 of Figure 1, showing the device for returning the pump to its neutral position when the doors reach their closed positions.

Figure 8 is an enlarged cross-sectional view of the suction check valve shown in Figure 1.

Figure 9 is an enlarged central vertical section 4 through the surge valve shown in Figures 1 and 2.

Figure 10 is an enlarged central vertical section through the door-controlling valve unit shown in- Figures 1 and 2.

In general (Figure 1) ing apparatus consists of the hydraulic compress itself, generally designated I a fluid tank, generally designated 2; a hydraulic pump for actuating the pressing cylinders, generally designated 3; another hydraulic pump for operating the doors of the compress, generally designated'l; a door controlling valve unit, generally designated 5; a relief and by-pass valve, generally designated 6; a surge valve adjacent to the main cylinder of the press-generally Vjdesignated l; a servomotor control valve, generally designated 8 for regulating the servo-moteiijwhich controls the discharge position of the pump 3; and a suction check valve, generally designated '9.

Hydraulic empress construction Referr' lg to the drawings in detail, Figure 1 shows the hydraulic'compress l of my invention associated with its auxiliary units and controls. The hydraulic compress itself comprises a main base Ill supported on' suitable foundation memmy hydraulic compresshers I and having side pillars |2 rising therefrom and supporting the compress head l3; the pillars |2 bear flanged portions I4 which serve to provide a bearing surface for the pillars |2 against the main base I and the compress head l3 respectively. The compress head I3 is held in place against the flanges I4 on the pillars l2, and these in turn held against the main base I, by suitable retaining members l5.

Beneath the main base I and associated therewith are the main hydraulic motor consisting of ,the main pressing cylinder l5 and the auxiliary hydraulic motors consisting of the auxiliary pressing cylinders which contain the main'ram l8 and auxiliary rams l9 respectively, these being attached at their upper ends to the compress platen which is moved up and down under the influence of the previously mentioned rams. platen 20 and the head l3 are provided with slots 2| in their opposing surfaces, these slots being adapted to receive binding members whereby the compressed materials may be baled and suitably held in their compressed positions.

The main base In of the compress carries brackets 22 which have bearing portions 23 suitably bored to pivotally receive shafts 24 passing therethrough. The shafts 24 carry the side doors 25 of the compress, each of these being provided with yoked portions 26 adapted to engage the shaft 24. The side doors 25 are provided with reinforcing Webs 21. The shafts 24 terminate in arms 28 (Figure 3) rigidly mounted thereon and pivotally connected at their free ends to the links 29 which in turn are connected at their opposite ends to the cross head 30.

The cross head 3|! is mounted upon the piston rod 3 l'having a piston head 32 (Figure 2) which is reciprocably mounted in the cylinder 33, this being closed at its open end by the closure member 34. The cylinder 33 is provided with ports 35 and 36 (Figure 3) for the passage of pressure fluid, whereby the piston head 32 is caused to move up or down, carrying with it the piston rod 3| and the cross head 30, thus raising or lowering the side doors 25 through the intermediate action of the links 29 and the arms 28 upon the door shafts 24.

The side doors 25 likewise carry arms 31 rigidly associated therewith and having at their outer ends a pivotal connection by pins 38 (Figure 3) to links 39 whose opposite ends are pivotally attached by pins 40 to the pivot supports 4| mounted on the false doors 42 associated with the hydraulic compress. The upper portions of the false doors 42 contain reinforcement members 43, whereas the lower portions carry arms 44 adapted to receive the pivot pins 45 through which they are pivotally connected to the brackets 46 mounted upon the door foundations 41 (Figure 3). The door foundation members I likewise carry door stops 48 which are arranged at such height that they serve as rests for the side doors 25 in their lowered positions. It will also be seen that when the side doors 25 are lowered by the action of the previously described mechanism, their arms 31 and associated links 39 will pull the false doors 42 into superposition on the side doors 25 (Figure 4). In this position the reinforcement members 43 of the false doors 42 serve as rests for the latter upon the side doors 25. Cooperating with the false doors 4?. are fixed platforms 49 which are arranged on the same level as theialse doors 42 when the latter are in their lowered positions.

The ends of the compress carry end plates 58 and 5| (Figure 2) which extend between the main The base In and the compress head I 3, and which serve as supports for the hydraulic motors consisting of the hydraulic cylinders 33, 52 and 53 which actuate the doors of the press. The cylinder 33 for actuating the side doors 25 is attached to the end plate 58. Also attached to the end plate 58 is a horizontal hydraulic cylinder 52, while immediately opposite it is a companion horizontal hydraulic cylinder 53 supported by the end plate 5| and reinforced therewith by a supporting arm 54 (Figure l).

The horizontal hydraulic cylinders 52 and 58 (Figure 2) contain piston heads 55 attached to piston rods 56 passing through closure members 51 in the open ends of the hydraulic cylinders 52 and 53. Attached to the opposite ends of the piston rods 56 are the end doors 58 (Figure 2),

the connection being made in the socket portions 59 of the end doors 58.

The end doors 58 carry reinforcing webs 68 and also are provided with recessed portions 6| (Figure 5) adapted to receive the edge projections 62 on the side doors 25. When the side doors 25 have been raised to their vertical positions, the end doors 58 are moved horizontally until their recessed portions 6| engage the edge projections 62 of the side doors 25 effectively interlocking the two sets of doors.

Hydraulic door operating mechanism The hydraulic cylinder 33 whose piston head 32 and piston rod 3| raise and lower the side doors 25, and the hydraulic cylinders 52 and 53, whose piston heads 55 and the piston rods 56 bring the end doors into their closed positions have already been described. The hydraulic cylinder 33 has ports 35 and 36 which communicate with pipe lines 63 and 64 respectively (Figure 1), leading to upper and lower ports 85 and 56 in the side door valve cylinder 61 of the door regulating valve 5.

Similarly, the end door operating cylinders 52 and 53 (Figure l) have ports 68 and 69 communicating with pipe lines 18 and 'l'l respectively. leading to lower and upper ports 73 and 7'. (Figure 2) of the end door operating valve cylinder '14 in the door operating valve unit 5. The valve cylinders 61 and 14 contain valve stems I5 and T6 respectively. The stem 15 is provided with enlarged heads 1'! and 18', whereas the stem 16 is provided with similar enlarged heads 79 and 80. These heads are spaced apart from one another by the same distance that separates the ports and 86, also the ports 12 and 13 respectively. Communicating with the central portion of the valve cylinders G1 and 14 is the pressure pipe line 8| having the cross pipe 82. Connecting the upper and lower ports 83 and 84 of the valve cylinder 61 is a branch pipe 85 joined to the discharge pipe 88. Connecting the upper and lower ports 81 and 88 of the valve cylinder 14 is a branch pipe 89 also joining the discharge pipe 85. The discharge pipe 26 leads back to the fluid tank 2, whereas the pressure pipe 8| leads to the door-operating pump 4. from which the suction line 90 leads back to the fluid tank 2.

The door-operating pump 4 (Figure '7) is a variable delivery rotary pump of the radial cylinder type. the general details of which form no part of this invention. The pump consists of a casing 9| closed by end plates 92 and 93: the latter holds a fixed hollow pintle 94. The pintle 94 serves for the introduction of fluid to a purality of radial cylinders 95 arranged with reciprocablc pistons 96 in a primary rotor or cylinder barrel 9'! which rotates freely around the pintle-SM. The cylinder barrel 9'! is connected to a drive shaft 98 passing through the end plate 92 and connected to a suitturn are secured to a secondary rotor I00. The secondary rotor I is rotatably mounted within the secondary rotor shifting ring IN and the latter connected to a shifting rod I02, whereby the shifting ring IOI may be moved laterally relative to the axis of the pintle 94. On the opposite side of the shifting ring IOI from the attachment of the shifting rod I02 is a piston rod I03 which is reciprocably mounted in a cylinder I04 attached to the pump casing 9I. The piston rod I03 carries a;

piston head I05 reciprocably mounted within the cylinder I04 and having its end portion in a chamber I06 with an outlet port I01. The outlet port M1 is connected by a branch pipe I08 leading to the pressure pip line 8|. The opposite end of the piston I05 lies within the chamber I09 closed by the threaded plug IIO. The chamber I09 communicates with the interior of the. pump casing 9| by way of the drilled passage III through the piston I05 and the piston rod I03.

The secondary rotor shifting. rod I02 of the pump 4 at its outer end bears a threaded portion I I2 upon which operates a hand wheel I I3 through the threaded nut II4 associated therewith. The hand wheel I I3 bears against a thrust hearing I I5,

engaging the opposite side of which is a sleeve I I6 reciprocably mounted in the bore III of the supporting portion II 8 mounted on the pump casing 9|. A compression coil spring II9 rests at one end against the pump casing 9| and at the opposite end against the end plate I20 of the sleeve I I6, urging the latter outward from the casing 9|.

The force with which this urging will take place is adjusted by turning the hand wheel I I3, which in turn moves the sleeve I I6 in or out and accordingly compresses or allows expansion of the spring H9.

The primary and secondary rotors 91 and I00 are mounted upon suitable anti-friction-bearings.

Surge valve construction The surge valve 1 is attached to the lower end of the main pressing cylinder I6 (Figures 1 and 9) and consists of a hollowcasing I2I within which is a bored chamber I22. The-bored chamber I22 is provided with four ports I23, I24, I25 and I26, the casing I2I being provided with annular enlargements where the first three of these ports enter it. The port I23 communicates with the tank 2 through the pipe I21. The port I24 opens into the main pressing cylinder I6 through the short'passageway I28. The port I25 is connected by the pipe I 29 to the head ports I30 and I3I of the auxiliary pressing cylinders I I, all of which are joined by the same pipe I29 to the pressure outlet I32 of the main pressing pump 3. Theline I33 continues from the line I29 beyond the outlet I32 and leads to the main cylinder relief and by-pass valve 6. The other pressure outlet I34'of the main pressing pump 3 communicates by the pipe line I35 with the ports I36 and 131 (Figure 1) at the upper ends of the auxiliary between the chambers I43-and 2I3.

the reverse direction.

.The chamber I43 is provided with ports 2I2 leading to the chamber 2I3 with its piston head I49. Reciprocably mounted between the chambers I and I42 is a piston I46 bearing a collar I41 against which presses a compression coil spring I48, whose opposite end rests against thepartition Likewise reciprocably mounted within the casing I 2| is a piston rod I 45, one end of which serves as a guide rod for the coil spring I48. The mid-portion and the opposite end of the piston rod I45 contain a pair of enlargedheads I49 and I50 spaced apart from one another and movable integrally with the piston rod I 45 by the action of fluid pressure. thereon within the chambers I 22 or 2I3 of the surge valve casing I2I. The check valve 2 is so arranged as to allow fluid to pass freely from the chamber I 43 to the chamber I, but not in The action of the piston I46 is resisted in one direction by the force of the coil spring I48 pressing against the collar I" on the piston rod I46.

vMain pressing pump construction The details of the main pressing pump 3 (Figures 1 and 2) form no part of this invention and are already known to the art. The main pressing pump 3 is a reversible variable delivery pump of any suitable type. The assembly shown is controlled by means of a servo-motor cylinder I5I mounted on one side of the casing of the main pressing pump 3, on the opposite side of which is the servo-motor valve assembly I52 having a reciprocable valve member therein communi-' eating with the valve rod I54 which in turn is pivotally attached to a lever I55 whose fulcrum I56 is movable under the influence of a piston attached to the piston rod I5'I, the latter being reciprocable in a second chamber within the casing of the servo-motor valve assembly I52 under the influence of pressure reaching it from the ppe line I33. The opposite end of the lever I 55 is pivotally connected to a piston rod I58 which enters and is reciprocably mounted within the pneumatic cylinder I59. Within the latter the piston rod I58 is provided with a head which is moved in either direction by compressed air reaching it through the air pipes I60 and I 6|, these being connected to a source of compressed air (not shown) and likewise motor control valve 8. l

'Adjustment of the servo-motor control valve 8 causes the piston rod I58 to moveaimor out, moving the lever I55 and accordingly the valve rod I54, thus causing the shifting ring of the main pressing pump 3 to be moved and thus varying the delivery of the pump. An excessive pressure arising in the pipe line I33 acts, on the piston of the piston rod I51 and moves it outward, causing the fulcrum I56 likewise to move outward, and hence tending to return the shifting ring of the main pressing pump 3 to its neutral or zero-delivery position.

to a servo- Construction of main cylinder relief and lay-pass valve needle valve rod I89 is extended through the walls of the fluid tank 2 so asto be adjusted from the outside thereof.

The bored chamber I63 also contains a piston rod I65 having attached thereto the spaced heads I66 and I61, the latter of which bears a further enlarged head I68 reciprocable within the bored chamber I69 beyond the bored chamber I63. The lower end of the piston rod I 65 is surrounded by a compression coil spring I10 resting against the piston head I68. The opposite end of the spring I19 rests against the end wall of a tubu-. lar cap I1I which is adjustably movable in or out of the casing" I62 by the threaded connection I72 therebetween. By turning the cap I1I, the compression force of the spring exerted upon the head I68 may be increased or decreased as desired.

The bore I63 is provided with a port I13 from which the pipe I33 runs back to the outlet I32 oft-he main pressing pump 3, and beyond it by the pipe line I29 to the surge valve and lower ends of the auxiliary pressing rfiylinders I1. Be-

yond the piston head I66 the bore I63 is provided with an outlet port I14 from which runs the pipe I38 back to the outlet I34 of the main pressing pump 3, and beyond it by the pull-back line I35 leading to the upper ends of the auxiliary pressing cylinders I1. From the lower part of the bore I63 to the lower end of the bore I64 runs the transverse passage I15, whereas from its upper end runs-a similar passage I16, these two passages being spaced apart from one another by a distance slightly less than the spacing of the heads I68 and I61 on the piston rod I65.

Reciprocably mounted in the bore I64 is a pis' ton rod I11 having a lower head I18 and an upper head I19 spaced therefrom, the latter having a further enlarged head I89 which is reciprocable within the enlarged extension bore I8I above the bore I64. The piston rod I11 at its upper end is surrounded by the compression coil spring I82 resting against the piston head I88. The opposite end of the spring I82 rests against the inner end wall of the adjusting cap I83 which engages the casing I62 in the threaded connection I84 therebetween. By turning the adjusting cap I83, the tension on the coil spring I82 may be increased or decreased, and the pressure exerted on the piston head I86 accordingly varied as desired. The upper end of the bore I8I is provided with outlet ports I85 communicating directly with the fluid in the tank 2, and thus allowing the free passage of fluid therethrough. The lower part of the bore I8I is provided with a port I86 for the same purpose as the ports I85.

The bored chamber I64 is provided at its lower end with a closure plug I81, and at its upper end with an outlet passage I88 which communicates directly with the fluid in the tank 2 in which the valve 6 is suspended.

The suction check valves 9 and 2H (Figures 1, 2 and 8) are of the ball type, providing unidirectional flow of fluid. They consist of a casing I92 having oppositely disposed ports I93 and I94 and an upper chamber I95 and a lower chamber I96. Between the upper chamber I95 and the lower chamber I96, the casing I92 is provided with a concave annular spherical portion I91, against which fits a ball I98. Thus it will be seen that the fluid can pass upward from the port I94 through the chamber I 96 into the chamber I 95 and through the port I 93 by merely pushing theball upward. .The chamber I95 is closed by a screw plug I99 which gives access to the ball I98. Back pressure developing in the pipe I93, however, will force the ball I98 downward against its seat I91 and prevent the escape of any fluid from the chamber I95 to the chamber I96.

Operation of the hydraulic cotton press It will be assumed that the press is at rest and that the end doors are pulled apart by causing their piston rods 56 to move away from one another, and also that the side doors 25 are in their horizontal positions with the false doors 42 superposed upon them, asshown in Figure 4. This is the loading position of the press. The platen 28 of the press (Figure 4) is, of course, in its lowest position. I

The cotton or other yieldable material to be compressed is usually brought to the press in the form of bundles or low density bales. The purpose of further compression is to greatly increase the density of these bales and thus cause them to occupy a smaller amount of space in the ship or car used for their further transportation. The loose bale is moved across the platform 49 (Figure 4) and the false door 42 on to the upper surface of the press platen 29. Suitable binding members are arranged in the slots 2,I

The door-operating pump 4 is now placed in operation by starting the electric motor or other power source which actuates it. The valve rod 15 of the door controlling valve unit 5 is then pushed upward into the position shown in Figure 2, thereby allowing pressure fluid to proceed from the door-operating pump 4 through the line 8I and the branch line 82 into the middle portion of the valve casing 61, thence outward through the port 65 and along the pipe 63 intothe upper part of the side door cylinder 33. The pressure fluid thus entering the latter chamber causes the piston 32 and the cross head 39 (Figure 3) to move downward, causing the links 29 to act upon the arms 28 and turn the shafts 24, thus raising the side doors 25 from their horizontal to their vertical positions. At the same time the arms 31 on the side doors 25 move upward and raise the false doors 42 through the intermediate action of the links 39 therebetween.

The valve rod 16 of the door-operating valve unit 5 is now raised to the position shown in Figure 2, so that pressure fluid flows from the door-operating pump 4 through the pipe 8| and the branch pipe 82 into the middle chamber of the valve casing 14, thence through the port 12 into the pipe H and thence into the outer chambers of the end door operating cylinders 52 and 53. The pressure fluid in these chambers then acts against the pistons 55, causing them to move inward and thus moving the end doors 58 toward one another (Figure 2) until their slotted portions 6| engage the ridged portions 62 (Figure 5) on the side doors 25, thus locking the end doors 58 and l 52 and 53 returns to the fluid tank 2 by way of the pipes 64 and 10 respectively, the door-operating valve unit 5, the branch pipes 85 and 89, and the return pipe 86. When the end doors 58 and the side doors 25 become thus interlocked, they can 10 move no farther, and pressure accordingly piles up in the door-operating cylinders 33, 52 and 53. This pressure backs up in the pipe lines 63 and 1 I, thence back through the pipe 8| and the branch pipe I08 into the chamber I06 (Figure 7) of the 18 cylinder I04 by way of the inlet port I01. The

cylinder I04, it will be recalled, is mounted on one side of the door-operating pump 4. The piston I05 is then caused to move to the left under the influence of the. pressure in the chamber I06,

20 overcoming the force of the compression spring H9, and pulling the secondary rotor I of the door-operating pump 4 toward its neutral or zerodischarge position. Thus the door-operating pump 4 tends to hold the pressure in-the door- 25 operating cylinders 33, 52 and 53, but not to increase this pressure beyond the amount determined by the force of the compression spring I I9 as adjusted by the hand wheel H3. Any fluid which chances to be in the chamber I09 in front 80 of the piston head I05 escapes through the drilled passage III into the interior of the pump casing 9|.

The servo-motor control valve 8 is now adjusted to cause the main pressing pump 3 to de- 35 liver pressure fluid into the pressing pipe line I29.

Atthis stage the surge valve members are assumed to be in the position shown in Figures 2 and 9, with the piston heads I46, I49 and I 50 moved to their extreme lefthand positions. The

40 pressure fluid now flows by way of the pressing line I 29 through the ports I30 and I3I of the auxiliary pressing cylinders I1, causing the pistons I9 thereof to move upward, compressing the cotton imprisoned between the end doors 58 and the side doors 25 against the platen 20 and the press head I3. Meanwhile fluid is sucked freely from the tank 2 through the pipe I21 into the middle portion of the bored chamber I22. and

thence upward through the passage I24 into the M main pressing cylinder I6.

The platen 20 thus continues to move upward, and the resistance it encounters becomes greater and greater as the cotton is further compressed, causing the pressure of the pressure fluid in the various chambers served by the pressing line I29 to increase as a consequence. When this pressure reaches a predetermined value in the cham her I M of the surge valve 1 (Figure 2), it overcomes the resistance of the coil spring I48, thus i5, causing the piston I46 to move in ward, allowing the pressurefluid to flow through the chamber I42, the ports I44, the chamber I43 and the ports 2I2 into the chamber 2 I3 behind the piston head I49, shifting the piston heads I49 and I50 to the 5 right of their positions shown in Figures 2 and 9.

In their thus displaced positions, the piston heads I49 and I50 respectively cover up the entrance port I23 from the tank pipe line I21 and uncover the inlet port I25 from the. pressing line 70 I29. Pressure fluid is enabled to flow from the pressing line I29 through the port I25 into the middle portion of th' bored chamber I22, thence into the main pressingcylinder I6 by way of the passage I24. The main pressing piston I8 now 75 moves upward under the influence of this presing pistons I9. The platen thus continues to rise and still further compress the cotton under the influence of all three pressing cylinders. When the pressing pressure has reached a predetermined maximum, the servo-motor valve unit I52 causes the shifter ring of the main pressing pump 3 to move to its neutral or zero-discharge position under the influence of the piston rod I51, changing the position of the fulcrum I56 (Fig. 1). The main pressing pump 3, therefore, continues to hold the pressure in the pressing cylinders I6 and I1, but not to increase it.

The door-operating valve unit 5 is now operated in the reverse direction, the valve rods 15 and 16 being moved downward. This causes pressure fluid to flow from the door-operating pump 4 through the line BI and the middlechambers' of the valve casings 61 and 14 through the pipes 64 and respectively to the space behind the piston heads 32'and 55 respectively. Under the influence of this pressure fluid, the piston heads 55 move away from one another carrying with them the end doors 58, andthus removing the recesses 6I thereof from their engagement with the ridged portions of the side doors 25. The latter are then free to move downward, and do so under the influence of the pressure fluid acting behind the piston head 32, causing it to move upward and hence moving the side doors 25 downward through the intermediate action of the links .29 and the arms 28 operatively connected thereto. The fluid displaced from the outer chambers of the cylinders 52 and 53 flows back to the fluid'tanks 2 by way of the pipe 1|, the upper chamber of the valve casing 14, the port 81, the branch pipe 89 and the return pipe 86 (Figure 2). Similarly, the fluid displaced from the upper chamber of the cylinder 33 returns to the fluid tank 2 by way of the pipe 63, the upper chamber of the valve casing 61, the port 83, the branch pipe 85 and the return back line I35 now delivers the pressure fluid and the pressing line I29 serves as' the return line.

At this stage the main cylinder relief and bypass valve 6 comes into operation. While the pressing pump 3 is operating the press in the pressing stroke, as previously described, the pressure fluid from the pressing line I29 backs up' through the pipe I33 into the middle portion of the bored chamber I63 (Figure 6), where it acts equally on the inner surfaces of the piston heads I66 and I61, hence fails to move them in either direction. The pressure fluid accordingly passes onward into the lower portion of the bored chamber I64 where it acts against the lower surface of the piston head I18 to force the piston rod I11 upward in opposition to the force of the compression coilspring I82. As it moves upward, the lower piston head I18 on the piston rod I11 fails to uncover any escapepassages; accordingly the pressure fluid is confined within the chambers previously mentioned.

At the instant the main pressing pump 3 is reversed, however, the pressure fluid now flows into cover the annular chamber 200.

the upper portion of the bored chamber I63 (Figure 6) from the pipe I38, and acts against the upper surface of the piston headI66, forcing the latter downward and uncovering the passage I16 leading into the middle portion of the bored chamber I64. The same downward motion of the piston rod I65 causes the piston head I61 to un- Meanwhile the piston rod I11 is held in its upper position by the pressure fluid under the piston head I18, causing the piston head I19 to uncover the exhaust passage I88.

Under these circumstances, the pressure fluid from the main cylinder flows through the bored chamber I63 into the enlarged chamber 200 and through the passages-2M and I9I into the tank 2. Meanwhile the discharge of the pressing pump 3 into the pull-back line I35 has been carried backward through the line I38 into the portion of the bored chamber I63 above the piston head I66 (Figure 6), thence through the transverse passage I16 and the bored chamber =I64 out through the exhaust port I88 into the tank 2.

Thus the action of the main cylinder relief and by-pass valve, as above described, causes the pressure in the main cylinder I6 to be relieved at the moment of the reversal ofthe pressing pump 3, and also causes the discharge of the latter pump to be temporarily by-passed through this valve into the fluid tank 2. When the pressure in the main cylinder. I6 has been relieved to such an extent that the pressure fluid coming therefrom by way of the pipe line I33 into the lower portionoi the bored chamber I64 is insufiicient to overcome the downward force of the coil spring I82, the piston rod I11 moves into the position shown in Figure 6, covering the exhaust port I88 and preventing the further escape of fluid from the pull-back line I38 through the transverse passage I16. The piston. head I66 remains in its downward position under the influence of the pressure in the pull-back line, but the pressure fluid thereof acts equally on the inner portions of the piston heads I18 and I19 and, therefore, fails to move the piston rod I11 in either direction. Fluid is still free to escape, however, from the main cylinder pipe line I33 through the bored chamber I63 and its annular enlargement 200 by way of the longitudinal conduit 2I1I into the exhaust port I9I and thence to the fluid tank 2.

At the same time the dropping of pressure in the main cylinder I6 and a consequent dropping of pressure in the pressing line I28 (Figure 2) causes the pressure likewise to drop in the chamber I4I of the surge valve 1, until it is insuflicient to resist the force of the coil spring I48, whereupon the piston head I46 moves to the left, and cuts oif communication between the chambers HI and I42. At the same time the pressure of the fluid from the pressure line I35 in the end of the chamber I22 forces the piston head I50 backwards, covering the port I25 and uncovering the port I23. The fluid discharged from the main cylinder during the pull-back operation is then free to pass through the pipe line I21 back into the fluid tank 2, whereas that from the auxiliary cylinders I1 passes through the pipe line I29 into the pressing pump 3, whence it is discharged under pressure through the pipe line I35 into the upper portion of the auxiliary cylinders I'I behind the pistons I9 thereof. Meanwhile the fluid trapped in the chamber I43 is expelled through the branch .pipe 2I0 and the check valve 2 into the chamber HI. 4

The highly compressed bale is now removed from the press and replaced by another bale, .whereupon the above cycle of operations is repeated.

The suction relief valve 9 operates to open when the pressing pump 3 is performing the pressing operation, withdrawing additional fluid through it from the tank 2. This additional fluid is needed to fill the main cylinder I6 when the line I38 is the suction line and the line I28 is the pressure line.

It will be understood that I desire to comprehend within my invention such modifications as maybe necessary to adapt it to varying conditions and uses.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A hydraulic compress comprising a stationary press head, a platen movable toward said press head, a main hydraulic piston and an auxiliary hydraulic piston connected to said platen, means for supplying pressure fluid initially to said auxiliary hydraulic piston until a predetermined pressure is reached thereat, means for thereafter supplying pressure fluid to said main hydraulic piston and said auxiliary hydraulic pistonsimultaneously, means for enclosing the space between said movable platen and said stationary head on all sides, said enclosing means comprising side and end doors hydraulically movable into closed positions, a hydraulic motor for closing said end doors, and another hydraulic motor for closing said side doors.

2. A hydraulic compress comprising a stationary press head, a movable platen, a pair of oppositely disposed horizontally pivoting side doors, a pair of oppositely disposed reciprocating end doors, a hydraulic motor to close said pivoting doors, another hydraulic motor to close said reciprocating doors, and means adapted to cause one set of said doors to move into closed position before the closing of the other set thereof.

3. A hydraulic compress comprising a stationary press head, a movable platen, a pair of oppositely disposed pivoting doors, a hydraulic motor to close said pivoting doors, a pair of oppositely disposed reciprocating doors, a hydraulic motor to close said reciprocating doors, and means adapted to prevent the motion of one set of doors until the other set of doors has moved into its closed position.

4. A hydraulic compress comprising a stationary press head, a hydraulically movable platen, reciprocable end closure members for said compress, hydraulic rams for reciprocating said end closure members, horizontally pivoted side closure members, and a hydraulic motor for closing said side closure members.

5. A hydraulic compress comprising a stationary press head, a hydraulically movable platen, reciprocable end closure members for said compress, horizontally reciprocable hydraulic rams for closing said end closure members, said end closure members being mounted upon said rams and reciprocable therewith, side closure members being pivotally movable on horizontal axes into their closed positions, and a hydraulic motor for closing said side closure members.

6. A hydraulic compress comprising a stationary press head, a hydraulically movable platen, a pair of oppositely disposed reciprocable end closure members for said compress, a pair of hydraulic rams for reciprocating said end closure members, side closure members pivotally movable on horizontal axes into their closed positions, and

a hydraulic motor for closing said side closure members. i

7. A hydraulic compress comprising a stationary press head, a platen movable upwardly by hydraulic means toward said stationary head, means comprising a pair of horizontally. reciprocating doors, and a pair of horizontally pivoting doors engaging one another for inclosing the compressed material on all of its lateral sides between said platen and said stationary head during the pressing operation, oppositely moving hydraulic rams for closing said reciprocating doors, and a separate hydraulic motor for closing said 5 pivoting doors.

' LESLIE S. I- IUIBBERT. 

